1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS ISO 11698-2:2000 ICS 3
2、7.080 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Micrographics Methods of measuring image quality produced by aperture card scanners Part 2: Quality criteria and controlThis British Standard, having been prepared under the direction of the DISC Board, was published under
3、the authority of the Standards Committee and comes into effect on 15 February 2001 BSI 02-2001 ISBN 0 580 36925 0 BS ISO 11698-2:2000 Amendments issued since publication Amd. No. Date Comments National foreword This British Standard reproduces verbatim ISO 11698-2:2000 and implements it as the UK na
4、tional standard. The UK participation in its preparation was entrusted by Technical Committee IDT/1, Document imaging applications, to Subcommittee IDT/1/1, Quality, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any
5、 enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references
6、 The British Standards which implement international publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British S
7、tandard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cov
8、er, an inside front cover, the ISO title page, pages ii to iv, pages 1 to 8, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.Reference number ISO 11698-2:2000(E) INTERNATIONAL STANDARD ISO 11698-2 First edition 20
9、00-08-01 Micrographics Methods of measuring image quality produced by aperture card scanners Part 2: Quality criteria and control Micrographie Mthodes de mesurage de la qualit de limage produite par les numriseurs de cartes fentre Partie 2: Critres et contrle de qualitISO11698-2:2000(E) ii ISO 11698
10、-2:2000(E)iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject
11、 for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC)
12、on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Internatio
13、nal Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this part of ISO 11698 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Interna
14、tional Standard ISO 11698-2 was prepared by Technical Committee ISO/TC 171, Document imaging applications, Subcommittee SC 1, Quality. ISO 11698 consists of the following parts, under the general title Micrographics Methods of measuring image quality produced by aperture card scanners: Part 1: Chara
15、cteristics of the test images Part 2: Quality criteria and control Annexes A and B of this part of ISO 11698 are for information only.ISO 11698-2:2000(E) iv Introduction Scanning of microimages in aperture cards for use in CAD and electronic information systems is of great importance. This Internati
16、onal Standard provides means of evaluating the output quality of images resulting from scanning of aperture card microimages. The procedures may be used to establish and maintain image quality achieved by a scanner. The specification of the test microimages can be found in ISO 11698-1.INTERNATIONAL
17、STANDARD ISO 11698-2:2000(E)1 Micrographics Methods of measuring image quality produced by aperture card scanners Part 2: Quality criteria and control 1 Scope This part of ISO 11698 specifies methods for using the test images specified in ISO 11698-1 to check the quality of images produced by apertu
18、re card scanners. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 11698. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, part
19、ies to agreements based on this part of ISO 11698 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain r
20、egisters of currently valid International Standards. ISO 3272-1:1983, Microfilming of technical drawings and other drawing office documents Part 1: Operating procedures. ISO 5457:1999, Technical product documentation Sizes and layout of drawing sheets. ISO 6196-1:1993, Micrographics Vocabulary Part
21、1: General terms. ISO 6196-4:1998, Micrographics Vocabulary Part 4: Materials and packaging. ISO 6196-5:1987, Micrographics Vocabulary Part 5: Quality of images, legibility, inspection. ISO 6196-6:1992, Micrographics Vocabulary Part 6: Equipment. ISO 6428:1982, Technical drawings Requirements for mi
22、crocopying. ISO 12651:1999, Electronic imaging Vocabulary. 3 Terms and definitions For the purposes of this part of ISO 11698, the terms and definitions in ISO 6196 and ISO 12651 apply. Where a term appears in both of these standards it is essential that the definition used is appropriate to the con
23、text of the term. The following terms and definitions also apply.ISO 11698-2:2000(E) 2 3.1 barrel distortion distortion in an image in which a specific point within the image is relatively farther from its optical axis than the corresponding point on the original, typified by a rectangle having one
24、of its sides bowed outward 3.2 image offsets adjustment device of a scanner that allows the capture size area to be moved relative to the nominal position that is specified in the relative International Standard for the aperture of an aperture card 3.3 pincushion distortion distortion in an image in
25、 which a specific point within the image is relatively closer to its optical axis than the corresponding point on the original, typified by a rectangle having one of its sides bowed inward 3.4 resolving power numerical expression of the limit of resolution of an imaging system, expressed as the numb
26、er of lines per millimetre discernible in an image of a test chart 3.5 scaling error relationship between the nominal and actual numbers of pixels or dots per length in an output electronic image 3.6 scanner offsets adjustments of the scanner system that calibrate the position of the capture area to
27、 be centralized over the standard card aperture area when image offsets are set to zero 3.7 test card aperture card or piece of photographic film having the same dimensions, containing a test image in the aperture or equivalent area 3.8 test image area of a test card that contains test targets, patt
28、erns, etc., intended for measuring quality of image produced by an aperture scanner 3.9 test target target comprising elements such as test charts, patterns and characters, used for assessing the quality of output from an imaging system 4 Methods of use 4.1 General Because of its impact on the accur
29、acy of other tests, evaluation of focus shall be made first. Other tests may be made in any order, taking account of interdependence of results as indicated in the method. Test images shall be scanned into an electronic imaging system. Output images, on screen or as hard copy, shall be examined to a
30、ssess quality level of characteristics. For a given bit-mapped image this may be different from its ultimate image on screen or as hard copy. Some characteristics shall be assessed by visual inspection, others by measurement. For measurement of screen images, a calibrated electronic viewing system b
31、y which any pixel in view can be displayed as an X direction and Y direction pixel count from a reference corner of an image shall be used. The linesISO 11698-2:2000(E)3 in the image shall be aligned within 2 with the corresponding axis of the measuring device of the viewing system. Errors in alignm
32、ent greater than two degrees are likely to affect the accuracy of scaling and capture size tests. For measurement of hard copy images, appropriate allowance shall be made for error introduced by the printer and it is essential that the magnitude of any printer error be determined by separate calibra
33、tion of the printer. Either or both methods may be used for evaluation but an electronic viewing measurement system is usually capable of producing more accurate results. No criteria for characteristics are specified. These are for the user to decide. 4.2 Establishing a quality reference To establis
34、h the quality reference the system shall be working at optimum level for all types of material to be scanned. Each of the test images specified in ISO 11698-1 1) and any other test image made by the user shall be scanned, regenerated as hard copy print of corresponding A size and evaluated. If the q
35、uality of the printed output is acceptable the prints shall be retained for reference and the reference bit-mapped images securely retained on a separate disk. All scanner adjustment settings and all other system settings used to make the reference prints shall be recorded. 5 Test methods 5.1 Focus
36、5.1.1 Set the scanner for the highest resolution and reduction ratio, and allows the full test image area to be scanned. 5.1.2 Scan a type 4 test image and display the resulting image on a monitor screen or print it. 5.1.3 Examine the test targets and record the letter of smallest pattern that can b
37、e resolved in each set of patterns in all the test targets. 5.1.4 Check that the lines ruled in the background area are clearly separate over the complete image area. NOTE Adjusting the focus of a scanner may require a special tool and procedures that are only available to service technicians. Howev
38、er, it is important to ensure that the quality of focus is maintained and this test image enables focus to be checked and measured. 5.2 Image centring 5.2.1 Set the scanner offsets correctly. 5.2.2 Set the image offsets to zero. 5.2.3 Load a type 1 test image into the scanner. 5.2.4 Scan the test im
39、age and display the resulting image on a monitor screen or print to fit a sheet of paper of size in the ISO A series. Note cut-off readings on the metric scales of one horizontally and one vertically connected pair. Calculate the deviation from centre in each direction by subtracting the smaller rea
40、ding from the larger one and dividing the result by two. For a paper print it will be necessary to correct the result for any deviation from nominal size of the sheet and any error in positioning introduced by the printer. 1) Test images are available from Applied Image Group/Imaging, 1653 East Main
41、 Street, Rochester, New York 14609 USA. Tel: (716) 482-0300. Fax: (716) 288-5989. Website address: E-mail address: ISO 11698-2:2000(E) 4 5.3 Image scaling 5.3.1 Set the scanner to scan the sheet size indicated on the type 1 test image to be scanned. 5.3.2 Set the pixel length and pixel width to the
42、 values obtained by multiplying the relative dimension of the sheet as specified in ISO 5457 by the scanning frequency in pixels per millimetre. 5.3.3 Set the reduction ratio to that specified in ISO 3272-1 for the sheet size being used. 5.3.4 Scan the test card and display the resulting image on a
43、monitor screen or print to the sheet size indicated on the test image, using a printer having printing resolution equivalent to that of the scanner. 5.3.5 On the screen image, using a calibrated electronic viewing system, determine the number of pixels along the lines HF and EG between the centre pi
44、xels in the perpendicular lines defining the ends of HF and EG. Divide the numbers obtained by the scanning resolution used in the test to give length of the lines in millimetres. 5.3.6 On the printed image measure the lengths of lines HF and EG to the nearest millimetre. Correct for any error due t
45、o inaccuracy in enlargement ratio of the printer. 5.4 Image capture size 5.4.1 Set the scanner to scan the sheet size indicated on the type 1 test image to be scanned. 5.4.2 Ensure that the scaling is correct as in 5.3. 5.4.3 Check that the pixel length and pixel width set for the sheet size corresp
46、ond to the standard ISO sheet size multiplied by the resolution to be used in the test. 5.4.4 Check that the reduction ratio set for the sheet size being used is equal to the nominal reduction ratio specified in ISO 3272-1 for the sheet size being used. 5.4.5 Scan the test image and display the resu
47、lting image on a monitor screen or print it. 5.4.6 Observe the display or the print. Absence of broken lines, with readings of 2,0 mm on each of the corner scales indicate correct image capture/scan size if there is no centring or scaling error. Whether or not broken lines are present, unequal readi
48、ngs on each corner scale indicate centring error. Equal readings on all the corner scales having a value other than 2,0 mm indicate scaling error. In interpreting the results of this test due allowance must be made for any error in centring or scaling revealed by tests in accordance with 5.2 and 5.3
49、. 5.5 Line straightness 5.5.1 Set the scanner to scan the sheet size indicated on the type 1 test image to be scanned. 5.5.2 Scan the test card and display the resulting image on a monitor screen or print it. 5.5.3 On the screen image, using a calibrated electronic viewing system in combination with a vector overlay facility, select each of the lines in the rectangular grid in turn and join each end by an overlaid vector line. Enlarge the display in regions of maximum deviation b
